218 ANNUAL KECOKD OF SCIENCE AND INDUSTRY. 



sides evidences of several distinct glacier systems. No very 

 high peaks occur in this region, the loftiest being only about 

 11,500 feet. There are many canons of great depth that 

 of the middle fork of American River measuring 3000 feet. 

 Upon the western slope of the Sierras there is much mineral 

 wealth, and the greater portion of this ore-bearing belt is 

 referred by Air. Conkling to the Archean period. Some valu- 

 able deposits also occur along the eastern slope. 



During this as in previous years, zoological work has been 

 prosecuted to the fullest extent practicable. Air. II. W. Hen- 

 shaw was attached as naturalist to the party whose area of 

 survey extended from Carson, New, northward along the 

 eastern slope of the Sierras, into the northern portion of Or- 

 egon. This region is exceptional in the number of large and 

 small lakes found within its limits, affording an opportunity 

 for studying the habits of western water-birds; and a large 

 series of skins and e^s was gathered. The avifauna of 

 this portion of the eastern slope was found to correspond 

 very closely with that of the region southward. Various 

 collections were also made in several branches of natural 

 history the fishes, grasshoppers, and butterflies receiving 

 special attention. 



The accumulation of data and material in the various 

 branches of the survey during this year is in excess of 

 the amounts obtained in any one of the former years. An 

 area of about 30,000 square miles was surveyed, admitting 

 of representation, says Lieutenant Wheeler, upon a scale of 

 one inch to two miles. Three base-lines were measured ; the 

 number of main and secondary triangulation stations oc- 

 cupied, and points established latitudinally by cross-sights 

 and the three-point method, was approximately 4000. The 

 altitude of a large number of stations on mountain - peaks 

 and at other prominent points was determined barometrical- 

 ly. More than 12,000 miles were meandered along roads and 

 streams. Extended observations were made to ascertain close- 

 ly the amount of arable, grazing, timber, mineral, and arid 

 areas surveyed ; and these examinations will hereafter form 

 one of the adjuncts of the topographical survey proper. The 

 parties disbanded at Ogden, Utah ; Carson, Nev. ; Fort Gar- 

 land, Col., and Fort Union, N. Mex., between November 

 25 and December 10, at the close of an extended field 



